Small update: I started hacking on that old seat pan again. The plan was to shorten the whole bike back to the arch and make the seat angle flush with the arch in the back to give it a uniform look. By shortening everything the seat was very wide at that point and I thought it just looked awkward. So I cut triangles out to get the angles right and I will weld the gap back closed now that the lines are right. Then sand blast the whole thing and paint it. Then I'll start shaping the seat foam to angle into the frame the same way. I got this idea from the way the seat is on newer crotch rockets, to help give perspective.